Transport effects of low (m,n) MHD modes on TFTR supershots

Z. Chang; E. D. Fredrickson; J. D. Callen; K. M. McGuire; M. G. Bell; R. V. Budny; C. E. Bush; D. S. Darrow; A. C. Janos; L. C. Johnson; H. K. Park; S. D. Scott; J. D. Strachan; E. J. Synakowski; G. Taylor; R. M. Wieland; M. C. Zarnstorff; S. J. Zweben

doi:10.1088/0029-5515/34/10/I03

Transport effects of low (m,n) MHD modes on TFTR supershots

Z. Chang, E. D. Fredrickson, J. D. Callen, K. M. McGuire, M. G. Bell, R. V. Budny, C. E. Bush, D. S. Darrow, A. C. Janos, L. C. Johnson, H. K. Park, S. D. Scott, J. D. Strachan, E. J. Synakowski, G. Taylor, R. M. Wieland, M. C. Zarnstorff, S. J. Zweben

Department of Physics

Stevens Institute of Technology

Research output: Contribution to journal › Article › peer-review

Abstract

Supershots in TFTR often suffer a performance deterioration characterized by a gradual decrease of the DD fusion neutron yield and plasma stored energy after several hundred milliseconds of auxiliary heating. The correlation between this performance deterioration and the development of low m (the poloidal mode number), n (the toroidal mode number) MHD modes is studied through shot-to-shot comparisons and statistical data analyses. A good correlation is observed between performance deterioration and the appearance of strong 3/2 and 4/3 macroscopic modes. The magnetic island structures are observed using Mirnov and ECE diagnostics. The measured T_e, T_i and n_e profiles show that development of the islands corresponds to a nearly constant decrement of these quantities over the core region r < r_s, where r_s is the mode rational surface, on a transport time-scale (t > τ_E). The observed energy deterioration scaling, δW/W varies as w/a, where w is the magnetic island width and a is the plasma minor radius, agrees with a local transport model. Numerical simulations based on the local transport model reveal many features consistent with the experiments. Besides the MHD effect, it is found that a continuous increase of edge recycling rate during the neutral beam injection phase also has a large effect on the performance deterioration.

Original language	English
Article number	I03
Pages (from-to)	1309-1336
Number of pages	28
Journal	Nuclear Fusion
Volume	34
Issue number	10
DOIs	https://doi.org/10.1088/0029-5515/34/10/I03
State	Published - 1994

ASJC Scopus subject areas

Nuclear and High Energy Physics
Condensed Matter Physics

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Chang, Z., Fredrickson, E. D., Callen, J. D., McGuire, K. M., Bell, M. G., Budny, R. V., Bush, C. E., Darrow, D. S., Janos, A. C., Johnson, L. C., Park, H. K., Scott, S. D., Strachan, J. D., Synakowski, E. J., Taylor, G., Wieland, R. M., Zarnstorff, M. C., & Zweben, S. J. (1994). Transport effects of low (m,n) MHD modes on TFTR supershots. Nuclear Fusion, 34(10), 1309-1336. Article I03. https://doi.org/10.1088/0029-5515/34/10/I03

@article{cdee96799f0347d3ba3255fe1cd81a27,

title = "Transport effects of low (m,n) MHD modes on TFTR supershots",

abstract = "Supershots in TFTR often suffer a performance deterioration characterized by a gradual decrease of the DD fusion neutron yield and plasma stored energy after several hundred milliseconds of auxiliary heating. The correlation between this performance deterioration and the development of low m (the poloidal mode number), n (the toroidal mode number) MHD modes is studied through shot-to-shot comparisons and statistical data analyses. A good correlation is observed between performance deterioration and the appearance of strong 3/2 and 4/3 macroscopic modes. The magnetic island structures are observed using Mirnov and ECE diagnostics. The measured Te, Ti and ne profiles show that development of the islands corresponds to a nearly constant decrement of these quantities over the core region r < rs, where rs is the mode rational surface, on a transport time-scale (t > τE). The observed energy deterioration scaling, δW/W varies as w/a, where w is the magnetic island width and a is the plasma minor radius, agrees with a local transport model. Numerical simulations based on the local transport model reveal many features consistent with the experiments. Besides the MHD effect, it is found that a continuous increase of edge recycling rate during the neutral beam injection phase also has a large effect on the performance deterioration.",

author = "Z. Chang and Fredrickson, {E. D.} and Callen, {J. D.} and McGuire, {K. M.} and Bell, {M. G.} and Budny, {R. V.} and Bush, {C. E.} and Darrow, {D. S.} and Janos, {A. C.} and Johnson, {L. C.} and Park, {H. K.} and Scott, {S. D.} and Strachan, {J. D.} and Synakowski, {E. J.} and G. Taylor and Wieland, {R. M.} and Zarnstorff, {M. C.} and Zweben, {S. J.}",

year = "1994",

doi = "10.1088/0029-5515/34/10/I03",

language = "English",

volume = "34",

pages = "1309--1336",

journal = "Nuclear Fusion",

issn = "0029-5515",

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Chang, Z, Fredrickson, ED, Callen, JD, McGuire, KM, Bell, MG, Budny, RV, Bush, CE, Darrow, DS, Janos, AC, Johnson, LC, Park, HK, Scott, SD, Strachan, JD, Synakowski, EJ, Taylor, G, Wieland, RM, Zarnstorff, MC & Zweben, SJ 1994, 'Transport effects of low (m,n) MHD modes on TFTR supershots', Nuclear Fusion, vol. 34, no. 10, I03, pp. 1309-1336. https://doi.org/10.1088/0029-5515/34/10/I03

TY - JOUR

T1 - Transport effects of low (m,n) MHD modes on TFTR supershots

AU - Chang, Z.

AU - Fredrickson, E. D.

AU - Callen, J. D.

AU - McGuire, K. M.

AU - Bell, M. G.

AU - Budny, R. V.

AU - Bush, C. E.

AU - Darrow, D. S.

AU - Janos, A. C.

AU - Johnson, L. C.

AU - Park, H. K.

AU - Scott, S. D.

AU - Strachan, J. D.

AU - Synakowski, E. J.

AU - Taylor, G.

AU - Wieland, R. M.

AU - Zarnstorff, M. C.

AU - Zweben, S. J.

PY - 1994

Y1 - 1994

N2 - Supershots in TFTR often suffer a performance deterioration characterized by a gradual decrease of the DD fusion neutron yield and plasma stored energy after several hundred milliseconds of auxiliary heating. The correlation between this performance deterioration and the development of low m (the poloidal mode number), n (the toroidal mode number) MHD modes is studied through shot-to-shot comparisons and statistical data analyses. A good correlation is observed between performance deterioration and the appearance of strong 3/2 and 4/3 macroscopic modes. The magnetic island structures are observed using Mirnov and ECE diagnostics. The measured Te, Ti and ne profiles show that development of the islands corresponds to a nearly constant decrement of these quantities over the core region r < rs, where rs is the mode rational surface, on a transport time-scale (t > τE). The observed energy deterioration scaling, δW/W varies as w/a, where w is the magnetic island width and a is the plasma minor radius, agrees with a local transport model. Numerical simulations based on the local transport model reveal many features consistent with the experiments. Besides the MHD effect, it is found that a continuous increase of edge recycling rate during the neutral beam injection phase also has a large effect on the performance deterioration.

AB - Supershots in TFTR often suffer a performance deterioration characterized by a gradual decrease of the DD fusion neutron yield and plasma stored energy after several hundred milliseconds of auxiliary heating. The correlation between this performance deterioration and the development of low m (the poloidal mode number), n (the toroidal mode number) MHD modes is studied through shot-to-shot comparisons and statistical data analyses. A good correlation is observed between performance deterioration and the appearance of strong 3/2 and 4/3 macroscopic modes. The magnetic island structures are observed using Mirnov and ECE diagnostics. The measured Te, Ti and ne profiles show that development of the islands corresponds to a nearly constant decrement of these quantities over the core region r < rs, where rs is the mode rational surface, on a transport time-scale (t > τE). The observed energy deterioration scaling, δW/W varies as w/a, where w is the magnetic island width and a is the plasma minor radius, agrees with a local transport model. Numerical simulations based on the local transport model reveal many features consistent with the experiments. Besides the MHD effect, it is found that a continuous increase of edge recycling rate during the neutral beam injection phase also has a large effect on the performance deterioration.

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U2 - 10.1088/0029-5515/34/10/I03

DO - 10.1088/0029-5515/34/10/I03

M3 - Article

SN - 0029-5515

VL - 34

SP - 1309

EP - 1336

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 10

M1 - I03

ER -

Transport effects of low (m,n) MHD modes on TFTR supershots

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